Ravi's papaya tree flowers every year but never bears fruit…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Ravi's papaya tree flowers every year but never bears fruit. A gardener says its flowers have stamens but no carpel. Explain why the tree bears no fruit, and what Ravi could do.
Need a reminder? The key ideaShow
The stamens (anther and filament) are the male parts and make pollen. The carpel (stigma, style and ovary) is the female part, with ovules in the ovary. Pollination brings pollen to the stigma, a pollen tube reaches the ovule, and fertilisation makes a zygote. The ovule becomes the seed and the ovary the fruit.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The fruit. A fruit grows from the ovary of a carpel, after fertilisation.
Step 2. This tree. Its flowers are unisexual and male: they have stamens but no carpel, so there is no ovary to become a fruit.
Step 3. What to do. Ravi could plant a papaya with female flowers nearby. His tree's pollen could then pollinate them.
Answer: a male tree has no carpels, so it cannot fruit; a female tree is needed, and his tree can supply its pollen.
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